"asymetric" performance with 2950 !?

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Aug 28th, 2007
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Hello !

I`m new to Cisco Switches and i could need some help for 2950 type of switches

we have performance problems between server and client - from what i can see at the "application" level it turns out that copying a file from client to server is dead slow and from the server to the client is quite fast. we have tried different constellations of servers/clients and it`s not a problem with the client/server itself. it looks like the uplink between those 2 ciscos has asymetric speed - just like an adsl line. (i.e. rx is around 10 times faster than tx)

any hints on what`s the best way to investigate into this?

is this probably a well known problem ?

sorry for asking, but i didn`t find much help on the net and just got aware of this forum.



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Joseph W. Doherty Tue, 08/28/2007 - 11:16
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Have you confirmed there are no duplex issues?

rkletzing Tue, 08/28/2007 - 11:27
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you mean tweaking negotiation appropriatly - i.e. testing if switching from autonegotiation to 100 fd/hd is making a difference ?

I had some issues with certain hosts not working properly because the switch ports were set on 100full and their network cards were set on auto. Probably they were constantly negotiating speed/duplex.

Problem was solved when I set the ports on the switch to auto.

Symptoms were something like you mentioned.

cyphur353 Tue, 08/28/2007 - 11:41
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Hard code the lines, or leave them both to auto. Mix and match doesn't work out so well.

purohit_810 Tue, 08/28/2007 - 12:55
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1) Do hard cap On port Speed and Duplex.

2) Also check flow control same configuratio AUTO/AUTO both end.

3)Check out if there is teaming at server end.

4) If you can't resolve with all above than PUT sniffer and see what happen why request doesn't flow fast.


Dharmesh Purohit

rkletzing Tue, 08/28/2007 - 13:04
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thanks for all your help - i will take a look very soon!

Joseph W. Doherty Tue, 08/28/2007 - 12:57
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Besides the duplex error, what else comes to mind is whether there any "strange" QoS configuration that might do something like rate limiting. Or, if you're using fiber between the switches, whether the one path is having errors and the other isn't.

Carefully check all interface stats along the path and also see what the load looks like.

If you transfers are using TCP, check for retransmits. (I like to use TTCP.)


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